Deformation of the moving magnetic skyrmion lattice in MnSi under electric current flow.

Topological defects are found ubiquitously in various kinds of matter, such as vortices in type-II superconductors, and magnetic skyrmions in chiral ferromagnets. While knowledge on the static behavior of magnetic skyrmions is accumulating steadily, their dynamics under forced flow is still a widely open issue. Here, we report the deformation of the moving magnetic skyrmion lattice in MnSi under electric current flow observed using small-angle neutron scattering. A spatially inhomogeneous rotation of the skyrmion lattice, with an inverse rotation sense for opposite sample edges, is observed for current densities greater than a threshold value j t ~ 1 MA m-2 (106 A m-2). Our result show that skyrmion lattices under current flow experience significant friction near the sample edges due to pinning, this being a critical effect that must be considered for anticipated skyrmion-based applications at the nanoscale.

Simvastatin improves morphological and functional recovery of sciatic nerve injury in Wistar rats.

AIM: The purpose of this work is to investigate the effects of simvastatin on sciatic nerve regeneration in male Wistar Rats. MATERIALS AND METHODS: Forty animals were allocated into four groups: (1) control (C); (2) control+simvastatin (CS); (3) lesioned animals+sterile PBS (LC) and (4) lesioned animals+simvastatin (LS). Lesioned animals were submitted to crushing lesion of right sciatic nerve. Simvastatin (20mg/kg/day, i.p.) was administered for five days. Footprints were obtained weekly for evaluation of functional locomotor recovery by means of the Sciatic Function Index (SFI). Blood samples were obtained weekly for quantifying circulating leukocytes. Animals were sacrificed after 21 days for histological analyses of sciatic nerve and spleen. RESULTS: LS Animals presented increased SFI scores, decreased areas of oedema and mononuclear cell infiltration during Wallerian degeneration and nerve regeneration (7,14 and 21 days; P<0.05). Spleen weight and white pulp areas was increased in LC animals after 21 days. Increased numbers of circulating neutrophils were observed in simvastatin treated animals (CS e LS) at seven, 14 and 21 days, compared to non-treated groups (C and LC). CONCLUSION: The study suggests that simvastatin accelerates the morphological and functional recovery process of the peripheral nervous system interfering with innate and acquired immunity.

Dual phasic suppression of viral replication following de novo human immunodeficiency virus type 1 (HIV-1) infection in lymphocytes of asymptomatic HIV-1 carriers.

Replication of human immunodeficiency virus type 1 (HIV-1) is suppressed in asymptomatic HIV-1 carriers (ACs). By using an in vitro experimental system, the mechanism of this suppression was investigated. Following in vitro infection of a laboratory HIV-1 strain, the peripheral blood mononuclear cells (PBMC) of ACs transiently supported a low level of viral replication, then the virus production rapidly decreased. PCR analysis revealed that HIV-1 proviral DNA integrated in the PBMC of ACs following infection gradually decreased. Such tapering consequences of in vitro HIV-1 infection in the PBMC of ACs were abrogated by depletion of CD8+ T cells from the culture. Furthermore, the viruses subsequently produced by the PBMC of an AC were less able to replicate than the virus produced by CD8+ cell-depleted PBMC of the same donor. These observations suggested that the CD8+ T cell-mediated suppression of HIV-1 replication in ACs may involve both cytocidal and cytostatic mechanisms: the former kills the cells producing viruses, and the latter inhibits viral spread by reducing viral infectivity.

Fatal angioedema associated with enalapril.

A 37-year-old female with a history of hypertension for 5 years was brought to the emergency room with swelling of the tongue and neck after the second dose of enalapril. After administration of hydrocortisone by her physician, she went to the emergency room. Her dyspnea and dysarthria were relieved. However, she experienced recurrence of the symptoms followed by respiratory arrest. She suffered severe anoxic brain damage and died three days later. Although angioedema is a rare occurrence with the use of enalapril, it is potentially life threatening.